the one with the chain guide looks like its from pe 250 80model or 81 i have mine off at the moment its 194 mm wide at pivot point no spacers and 232 mm inside at axle point from new only pe models had grease nipples the other one is not rm 125 n or t as i have both of these bikes , i think the pe 175s had the brake pivot through the swing arms but i dont have any info on them